At some point, if you use a plant protein powder supplement, you’ll probably hear that it’s “contaminated” with heavy metals and other potential toxins.
You may have seen headlines like this:
“Clean Label Project Finds Hidden Toxins in Protein Powders”
“Your Protein Powder Might Be Contaminated with Toxins, Says Consumer’s Reports”
“Study Finds Some Protein Powders Are Toxic To Your Health”
I can tell you with conviction that after poring over dozens of research studies, speaking to actual nutrition scientists, and reading all the hoopla about this topic online, there’s a lot of misinformation out there right now!
That’s why in this article, I want to separate the facts from myths regarding heavy metals in your plant protein powder and other foods.
This analysis is based on scientific data from peer-reviewed, placebo-controlled research studies (the gold standard of scientific research). All claims you see have a source, and you will see a list of all these sources at the end of the piece.
My objective when compiling research for this article was simple:
Find out what levels of heavy metals in foods/drinks are considered toxic / safe, according to the latest research.
Below you’ll find a summary of topics we’ll cover. This is a beast of an article at 3,000+ words, so click/tap on the topic you’re interested in if you want to to skip around.
Heavy metals are naturally occurring elements that have a high atomic weight and a density at least 5 times greater than water.
Some heavy metals (zinc, copper, and iron, for example) are considered trace minerals that are essential for biological function in animals. But absorbing high amounts of certain metals in your bloodstream may cause serious health issues (you’ll learn what those are in a minute).
Heavy metals are naturally present in water and soil, which means there are trace amounts in most fruits, vegetables, and tap water. They are not added to protein powders and other foods; rather, they’re absorbed from the soil by the plant.
Crops grown in heavily polluted soils in industrial areas (China is an infamous example) contain higher levels of metals.
The Clean Label Project, according to its website, is “a nonprofit focused on health and transparency in consumer product labeling.”
It’s ironic that they market themselves as such, for several reasons:
- They won’t disclose who they’re funded by.
- The methodology of their star rating system has come under heavy scrutiny for its subjectivity (more on this in a second).
- They conveniently just started offering certification services along with an online marketplace:
In its recent analysis of plant-based protein powders, the Clean Label Project assigned each product a score based on four criteria: heavy metals, pesticides, contaminants like BPA, and nutrition. Then it calculated an overall score.
The heavy metal levels accounted for 60 percent of the overall score. Why, exactly? There’s no scientific rationale.
The five products that received the poorest overall scores were:
- Garden of Life Organic Shake & Meal Replacement Chocolate Raw Organic Meal
- Nature’s Best Isopure Creamy Vanilla Zero Carb
- Quest Chocolate Milkshake Protein Powder
- 360Cut Performance Supplements 360PRO Whey Chocolate Silk Premium Whey Protein
- Vega Sport Plant-Based Vanilla Performance Protein
I don’t like any of these products, personally.
However, the amount of heavy metals in most protein supplements reviewed by The Clean Label Project are well below the “at-risk” levels. (See “Safety and Toxicity Levels of Lead, Cadmium, Arsenic, and Mercury“).
Do I think there’s value in knowing if BPA, pesticides, and unsafe levels of heavy metals are in your protein powder?
But here’s the bottom line: the Clean Label Project stands to make a handsome profit by convincing you that heavy metals are more dangerous than chemical pesticides and BPA (and added sugar, for that matter).
The Clean Label Project “study” is a brilliant piece of marketing, no doubt … it just doesn’t stand up to scientific scrutiny …
As a scientist, I’m deeply troubled by the methods the Clean Label Project used in its study and report. I trust that the organization and its leaders have good intentions, but their eagerness to warn consumers about contaminants may have caused them to overlook some basic scientific principles.
Lori Bestervelt, Ph.D.
“Prop 65”, or Proposition 65, is a law specific to the State of California that requires products sold in California to carry warnings about potential exposure to a list of 900 substances “known to the state” to cause a potential threat to health.
California’s daily limit for lead, in particular, is 0.5 mcg (or ppm), which is 20-50x more stringent than acceptable levels established by the World Health Organization, National Science Foundation, and EPA. See “Safety and Toxicity Levels of Lead, Cadmium, Arsenic, and Mercury“.
Whether the soil is certified organic or conventional, and regardless of whether the plant is organic or genetically modified, lead is naturally found in a single serving of many fruits and vegetables at levels that commonly exceed the Prop 65 limit of 0.5 mcg.
For example, a serving of turnips, apples, artichokes, carrots, cucumbers, green beans, spinach, brown rice, almonds and other nuts contain measurable amounts considerably higher than the artificial limits established in Prop 65.
Yet these food products don’t have to carry the warning label because they’re not classified as supplements.
Doesn’t matter where the proteins were grown either …
When the State of California conducted a soil-lead-uptake analysis of its own soil, from 70 different locations, they found that most vegetables averaged four times the Prop 65 lead limits. 
In the last 10 years, the issue of Proposition 65 warnings with respect to foods has become an increasingly hot topic of debate and litigation.
Legal proceedings to enforce Prop 65 against manufacturers are instituted by the State of California, private attorneys, or private citizen “bounty hunters”, who collect tens of millions of dollars every year. It’s spawned an industry of opportunists hoping to make a quick buck.
Read more about Prop 65 on The Center for Accountability in Science website.
Toxicity levels of heavy metals depend on several factors, including:
- Route of exposure and chemical species
- Age, gender, genetics, and nutritional status of exposed individuals
The heavy metals arsenic, cadmium, chromium, and nickel are classified as Group 1 human carcinogens (known or probable) according to the U.S. Environmental Protection Agency and the International Agency for Research on Cancer. 
However, in this article we will focus on the four heavy metals most commonly found in protein powders: arsenic, cadmium, lead, and mercury.
Let’s break down the important facts, starting with arsenic:
- Arsenic is found in small doses in many foods and in drinking water and plays a role in some biological processes in humans.
- The WHO recommended maximum intake of arsenic per day from drinking water is 10 ug.
- The highest total arsenic levels have been measured in the following foods: fish and seafood, products or supplements based on algae, and cereal and cereal products, with particularly high concentrations in rice grains and rice-based products and bran and germ.
- Contaminated water used for drinking, food preparation and irrigation of food crops poses the greatest threat to public health from arsenic.
What Is Arsenic?
Arsenic is found in small doses in many foods and in drinking water. Arsenic has a role in the metabolism of the amino acid methionine and in gene silencing, which means it’s a mineral your body actually needs.
But nonetheless, elevated levels of this mineral are highly toxic and very dangerous, particularly in its “inorganic” form (more on this in a minute).
How Arsenic Can Impact Your Health
Long-term exposure to arsenic from drinking-water and food can cause cancer and skin lesions. It has also been associated with cardiovascular disease and diabetes. In utero and early childhood exposure has been linked to negative impacts on cognitive development and increased deaths in young adults. 
Contaminated water used for drinking, food preparation and irrigation of food crops poses the greatest threat to human health from arsenic, according to the World Health Organization. 
The WHO also says that preventing further exposure to arsenic by avoiding water with high levels of arsenic is the most important action affected communities can take. 
Inorganic Vs Organic Arsenic
Inorganic arsenic compounds (such as those found in water) are highly toxic while organic arsenic compounds (such as those found in seafood) are less harmful to health. That’s because ingested organic arsenic compounds are much less extensively metabolized and more rapidly eliminated in urine than inorganic arsenic in both laboratory animals and humans. 
Arsenic Food and Drink Daily Limits
Current World Health Organization daily limits of arsenic in drinking water are 10 μg/L.  Arsenic can cause a number of human health effects at levels higher than this. [5, 6]
A 2010 research review published by the European Food Safety Authority found that the dose of inorganic arsenic consumed from food or drinks that would produce a 1% increased risk of developing cancers of the skin, urinary bladder and lung, ranged from 0.3 to 8 μg/kg of bodyweight.  That’s 20 – 544 ug/day for a 150-pound person.
Based on its testing, in 2016 the FDA proposed an action level, or limit, of 100 parts per billion (ppb) for inorganic arsenic in infant rice cereal. This level, which is based on the FDA’s assessment of a large body of scientific information, seeks to reduce infant exposure to inorganic arsenic. 
The proposed limit stems from extensive testing of rice and non-rice products, a 2016 FDA risk assessment that analyzed scientific studies showing an association between adverse pregnancy outcomes and neurological effects in early life with inorganic arsenic exposure, and an evaluation of the feasibility of reducing inorganic arsenic in infant rice cereal. 
- Cadmium (Cd) is an element found in the environment from natural occurrence and contamination.
- Cadmium is also present in trace amounts in certain foods such as leafy vegetables, potatoes, cereals, grains and seeds, liver, and crustaceans and mollusks.
- A small amount of the cadmium in food and water (about 1-10%) will enter your body through the digestive tract. If you do not have enough iron or other nutrients in your diet, you are likely to take up more cadmium from your food than usual.
- Cadmium contamination can cause kidney failure and bone demineralization.
- Safe daily levels of Cd should be kept below 24-30 ug per person per day.
- Smokers have the highest exposure to cadmium with food being the highest source of cadmium for the non-smoking population.
What Is Cadmium?
Cadmium (Cd) is a soft, silver-white metal found commonly in the environment from natural bioaccumulation and contamination.  Cadmium is also present in trace amounts in certain foods such as leafy vegetables, potatoes, cereals, grains and seeds, liver, and crustaceans and mollusks 
A small amount of the cadmium in food and water (about 1-10%) will enter your body through the digestive tract.  If you do not have enough iron or other nutrients in your diet, you are likely to take up more cadmium from your food than usual. 
How Cadmium Can Impact Your Health
Cadmium contamination is of concern because it can cause kidney failure and bone demineralization.  It can also cause respiratory and cardiovascular effects, skeletal lesions, and developmental issues in pregnant women, according to animal studies. 
Cadmium Food and Drink Daily Limits
Safe daily levels of Cd intake should be kept below 30 ug per person per day, according to a study published in the British Journal of Nutrition.  The European Food Safety Authority’s Panel says that a tolerable weekly intake for cadmium should be 2.5 micrograms per kilogram of body weight or less, or 24 ug/day for a 150-lb person. 
Individual variations in Cd absorption and sensitivity to toxicity predicts that a dietary Cd intake of 30 mcg/d may result in a slight renal dysfunction in about 1% of the adult population. 
Smokers have the highest exposure to cadmium with food being the highest source of cadmium for the non-smoking population. 
Due to their high consumption of cereals, nuts, oilseeds and pulses, vegetarians can have a higher dietary exposure. 
- Lead is a cumulative toxin that affects multiple body systems and may be particularly harmful to young children.
- Lead in the body is distributed to the brain, liver, kidney and bones. It is stored in the teeth and bones, where it accumulates over time. Human exposure is usually assessed through the measurement of lead in blood.
- People can become exposed to lead through occupational and environmental sources.
- Experts currently use a reference level of 5 micrograms per deciliter to identify children with blood lead levels that are much higher than most children’s levels.
- Lead absorption for adults is normally in the range of 5-10% of dietary lead. Children absorb 4-5 times more than adults.
- If you eat foods high in calcium, iron, and Vitamin C, your body will absorb less lead from food and drinks
What Is Lead?
Lead is a naturally occurring metal found in the Earth’s crust. Its widespread use has resulted in extensive environmental contamination, human exposure and significant public health problems in many parts of the world, particularly in developing countries and cities that still use lead pipes to transport drinking water.
How Lead Can Impact Your Health
At high doses, lead has been shown to hinder neuronal development, particularly in infants.
Today, the largest source of lead poisoning in children comes from dust and chips from deteriorating lead paint on interior surfaces.
Lead Food and Drink Daily Limits
Here’s what we know about lead, based on the latest research:
- The National Toxicology Program says that there is sufficient evidence for adverse health effects in children and adults at BLL <5 μg/dL. At doses higher than this, lead has been shown to hinder neuronal development, particularly in infants. .
- The National Health and Nutrition Examination Survey (NHANES) says that 5 micrograms per deciliter (5 μg/dL) is a blood lead level higher than 97.5% of children and no safe level has been established for children … so parents would be wise to avoid dietary exposure to lead in their young children whenever possible .
Keep in mind these are blood lead levels. Just because you eat a serving of Brussel’s sprouts (or sweet potatoes, spinach or protein powder), doesn’t mean your body will absorb the entire 7.9 mcg in one serving …
Lead absorption for adults is normally in the range of 5-10% of dietary lead. Children absorb more than adults …exactly how much more is unknown. 
Here are some examples of common foods that contain high amounts of lead:
If your dinner this week contains just one of the foods above, you’re ingesting more lead than you would in a serving of plant protein powder.
If you eat foods high in calcium, iron, and Vitamin C, your body will absorb less lead from food and drinks. 
It should go without saying, but if you have concerns about your (or your child’s) blood levels, ask your doctor for a blood test.
Mercury poses risks to the development children in utero and in early life. 
Mercury is not detected in the overwhelming majority of protein powders, so I’m not going to spend a lot of time on it.
The highest observed reading in the Clean Label Project analysis was 26.6 μg/kg, or approx. 0.8 μg per serving.
A tolerable amount has been set by the World Health Organization of 1.6 μg/kg bodyweight, per week, or around 17 μg per day for an average weight woman.  The amount per serving in the highest detectable level of mercury is around 4% of this tolerable daily amount.
Most people have mercury levels in their bodies below the level associated with possible health effects. Mercury settles into bodies of water like lakes and streams, or onto land, where it can be washed into water. That’s why fish and shellfish are most commonly associated with high mercury levels. If your mercury levels are high, eat less large fish like tuna, swordfish, and grouper. 
Arsenic: 10 ppm Lead: 4.1 ppm Cadmium: 10 ppm Mercury: 2 ppb Arsenic: 10 ppm Lead: 6 ppm Cadmium: 20 ppm Mercury: 20.3 ppb Arsenic: 20 ppm Lead: 10 ppm Cadmium: 10-30 ppm Mercury: 4 ppb
World Health Organization (WHO)
National Science Foundation (NSF)
Environmental Protection Agency
Arsenic: 10 ppm
Lead: 4.1 ppm
Cadmium: 10 ppm
Mercury: 2 ppb
Arsenic: 10 ppm
Lead: 6 ppm
Cadmium: 20 ppm
Mercury: 20.3 ppb
Arsenic: 20 ppm
Lead: 10 ppm
Cadmium: 10-30 ppm
Mercury: 4 ppb
The presence of a heavy metal does not equate to toxicity in the body or harm resulting from it. Like any vitamin or mineral, the frequency, dose, and exposure defines the poison–remember that most vitamins and vitamins are toxic in excessive amounts.
In the words of –Cliff Harvey, Ph.D., nutritionist, author, and research scientist:
Don’t freak out….the heavy metal levels in proteins tested were low and similar to what you’d get from foods in your normal, daily diet.
With that said, overexposure to heavy metal contaminants is a major public health concern, particularly in the developing world. While we need to be vigilant to ensure that our food and the supplements we use are not exposing us to risk, the heavy metal hysteria and the way it has been interpreted and reported in the mainstream media appears to be mostly fear-mongering.
Pure Food, like all plant-based protein powders, contains trace amounts of heavy metals. The amount you’ll find in our protein powder is much less than you’d get eating a serving of spinach, a handful of nuts, or a glass of wine.
Our products have all been 3rd party tested to monitor heavy metal levels, pesticides, and BPA (we don’t have detectable levels of the latter two). Our ingredients far surpass standard levels set by organizations including the World Health Organization (WHO), US FDA, EPA, National Science Foundation, European Union, and Canadian Natural Health Products Directorate. Those test results are all published on our FAQ page, by the way.
I still recommend choosing proteins that are sourced in the U.S. and Canada because the soil in places like China tends to be more heavily polluted.
As a parent of two young children, one of whom my wife is still breastfeeding, I do think it’s important to limit dietary exposure to lead and other heavy metals … the evidence suggests that moms who are pregnant or nursing should not be guzzling protein shakes and eating tuna every day.
Like anything else, moderation is key.
If heavy metals concern you, go get your (or your kids’) blood tested by your doctor. This will tell you if you have elevated levels. Side note: I got mine tested because I use 1-2 servings per day of Pure Food … mine were completely normal.
If you have questions or comments, feel free to leave it below.